Macrofilamentary tire yarns

ABSTRACT

A pneumatic tire reinforcement element comprising a single bundle of continuous macrofilaments of synthetic polymeric material selected from the group consisting of polyester and polyamide, wherein each macrofilament has a denier in the range 100 to 1,500, and the bundle has a total denier of 1,000 to 10,000 and a twist level not exceeding 4 turns per inch.

Unified Siaies Paieni Wilson et a1,

1 1 Well. 1, i972 [S41 M AQRGFKLAMENTARY TRIKE YARNS [72] inventors: Donald James Wilson; Derek Kenyon, l-iarrogate, England imperial Chemical Industries Limited, London, England [22] Filed: Nov.3,1969

[21] Appi.No.: 874,083

[73] Assignee:

[30] Foreign Application Priority Data May 11, 1968 Great Britain ..52,416/68 [51] lint. C1 .3602 9/00, D02g 3/48 [58] Field of Search .57/139, 140; 152/359, 358

[56] Reierenees Cited UNITED STATES PATENTS 3,253,638 7 5/1966 Kersker et a1 ..152/359 Nakazawa ..57/ 140 Primary Examiner-Donald E Watkins Attorney-Cushman, Darby &. Cushman {57] ABSTRACT A pneumatic tire reinforcement element comprising a single bundle of continuous macrofilaments of synthetic polymeric material selected from the group consisting of polyester and polyamide, wherein each macrofilament has a denier in the range 100 to 1,500, and the bundle has a total denier of 1,000 to 10,000 and a twist level not exceeding 4 turns per inch.

9 Claims, N0 Drawings MACROFELAMENTARY TIRE YARNS The present invention relates to filamentary yarns composed of macrofilaments and to pneumatic tires manufactured therewith By macrofilament used herein is meant a monofilament having a denier greater than 50.

Textile filamentary cords have previously been described for use in the manufacture of pneumatic tires. A typical exam pie is a cord formed from synthetic filaments by twisting a plurality of such filaments to form a yarn and then twisting together a number of these filamentary yarns. Each of the filaments in the cord has a denier of at least 10.

According to the present invention, there is provided a synthetic filamentary yarn having a total denier of 1,000 to 10,000, which comprises a plurality of macrofilaments, each macrofilament having a denier in the range 100 to 1,500, and which has a twist level not exceeding 4, turns per inch.

Also, according to the invention, a pneumatic tire comprises a tire building element, for example a breaker structure, incorporating synthetic filamentary yarns as defined in the preceding paragraph.

In one pneumatic tire construction, for example a radial-ply tire, the breaker structure may comprise two or more plies of yarns according to the invention. In each breaker ply, the yarns may be disposed at zero inclination or a small angle only, not exceeding 20, to the midcircumferential plane of the tire; and the yarns in one breaker ply may be disposed at zero inclination or at an angle, not exceeding 40, to those in the adjacent breaker ply or plies.

Preferably, a yarn in accordance with the invention is formed from polyester or polyamide macrofilaments.

The preferred range of macrofilament denier is 200 to 700, desirably 400 to 600, and the total denier of the yarn is preferably in the range 2,000 to 5,000. It is preferable for each rnacrofilament in the yarn to be of the same denier.

Although the number of macrofilaments forming the yarn is variable, for a given total yarn denier, it is preferred that the number of macrofilaments should be at least three and not greater than 20, and desirably should be seven.

Therefore, according to a preferred embodiment of the invention, a synthetic filamentary yarn comprises seven synthetic macrofilaments, each of which has the same denier in the range 400 to 600, and the yarn has inserted therein about 2 turns per inch twist.

This preferred yarn is circular in cross section and consequently has excellent packing characteristics coupled with desirable physical properties.

The tenacity of each synthetic macrofilarnent is preferably greater than 5 grams per denier.

The low twist yarns of the invention are preferably heat treated to modify certain yarn properties, for example shrinkage, prior to use. They may, for instance, be heat stretched or heat relaxed. The precise nature and temperature of such treatments will largely depend on the polymer from which the macrofilaments are formed.

The yarns according to the invention exhibit a high compression modulus compared with known textile reinforcement materials, resulting in breaker structures of increased planar rigidity per unit weight of reinforcement material. Considering the breaker structure as being a planar laminate structure consisting of two or more reinforcing plies, then the planar rigidity of the structure is defined as the resistance to shear and bending of the structure in the plane parallel with the reinforcing plies. When the breaker structure is forming part of a tire then this plane corresponds to the plane of the road contact patch of the tire.

The yarns are particularly useful when used directly as reinforcement materials in pneumatic tires. The yarn may be supplied to tire manufacturers directly in the form suitable for use in tires or may be made into this form by the tire manufacturers from macrofilaments by a simple single-twisting operation,

What we claim is:

1. A pneumatic tire reinforcement element comprising a single bundle of continuous macrofilarnents of synthetic polymeric material selected from the group consisting of polyester and polyamide, wherein each macrofilament has a denier in the range to 1,500, and the bundle has a total denier of 1,000 to 10,000 and a twist level not exceeding 4 turns per inch.

2. A reinforcement element according to claim 11, wherein the total denier of the element is in the range 2,000 to 5,000.

3. A reinforcement element according to claim 1, wherein the range of macrofilament denier is 200 to 700.

4. A reinforcement element according to claim 1, wherein the range of macrofilament denier is 400 to 600.

5. A reinforcement element according to claim 1, wherein the macrofilaments in the element have the same denier.

6. A reinforcement element according to claim 1, wherein the number of macrofilaments is at least three and not greater than 20.

7. A synthetic filamentary element comprising seven synthetic macrofilaments, each of which has the same denier in the range 400 to 600, and the yarn has inserted therein about 2 turns per inch.

8. A reinforcing element according to claim 7, wherein the macrofilaments are made of a material selected from the group consisting of polyester and polyamide.

9. A pneumatic tire comprising a tire building member incorporating reinforcement elements each of which comprises a single bundle of continuous macrofilaments of synthetic polymeric material selected from the group consisting of polyester and polyamide, and wherein each macrofilamcnt has a denier in the range 100 to 1,500, and each bundle has a total denier of 1,000 to 10,000 and a twist level not exceeding 4 turns per inch. 

2. A reinforcement element according to claim 1, wherein the total denier of the element is in the range 2,000 to 5,000.
 3. A reinforcement element according to claim 1, wherein the range of macrofilament denier is 200 to
 700. 4. A reinforcement element according to claim 1, wherein the range of macrofilament denier is 400 to
 600. 5. A reinforcement element according to claim 1, wherein the macrofilaments in the element have the same denier.
 6. A reinforcement element according to claim 1, wherein the number of macrofilaments is at least three and not greater than
 20. 7. A synthetic filamentary element comprising seven synthetic macrofilaments, each of which has the same denier in the range 400 to 600, and the yarn has inserted therein about 2 turns per inch.
 8. A reinforcing element according to claim 7, wherein the macrofilaments are made of a material selected from the group consisting of polyester and polyamide.
 9. A pneumatic tire comprising a tire building member incorporating reinforcement elements each of which comprises a single bundle of continuous macrofilaments of synthetic polymeric material selected from the group consisting of polyester and polyamide, and wherein each macrofilament has a denier in the range 100 to 1,500, and each bundle has a total denier of 1,000 to 10,000 and a twist level not exceeding 4 turns per inch. 